I Tried to mod my Bios (Insyde F.24) which I want to change only the logo (the others modules are okey, I don't need to whitelist some WLAN chip or something like that, but just change the Logo). I tried with EzH2O and doing it manually with Phoenix, but I can't flash it, either with InsydeFlash (from HP or from the web) or using the HP Dyagnostic program from BIOS (POST->ESC->F2).

From InsydeFlash (HP) I got "The update is locked in this device". Also in the log I can see "The BIOS image is corrupted or does not contain the correct digital signature."

From InsydeFlash (Web) I got LOAD_DRIVER_FAIL (just the code, I got the name in the platform.ini)

From HP Dyagnostic I got something similar as the InsydeFlash (HP).

I though that my Bios has RSA (as everybody says that HP is using that from 2012, and my computer is from 2014 I think), but Phoenixtool doesn't say anything of "Decrypted", also if I use hewprsa.exe in the original .fd I got:

So I don't know if the RSA rule is going on in my case. But, if I do a copy of my BIOS using the InsydeFlash (HP's wizard) I can get a .s12 file that, if I'm correct, is the sign file (in fact, if I try to flash using the HP Dyagnostic, if the .s12 is missing I will get the error "Signing file is missing", but if I use that .s12 with my modded firmware, I get "Signin file not valid").

Finally, here is my original Firmware, the .s12 file, two Modded Firmware, and the image that I'm using (Note that the image has the exact pixel size as the original one, and its weight is the half of the original): https://mega.nz/#!69YiTCgA!FfzEXbguroTlz...T5Vs67swic
(The Logo GUID is 7DE8E5CC-C270-4BF4-A4D3-F653A17ED21E_2113, or at least starts with 7DE8E5CC).